The present invention relates to a data printing device used in a camera to print data such as date and/or time on a frame of a roll of film.
A conventional data printing device includes a light emitting device and an imaging optical system. The light emitting device includes a plurality of LEDs (light emitting diodes) aligned along a line perpendicular to a winding direction of a roll of film and the imaging optical system forms light points corresponding to the LEDs on the film. The LEDs are controlled in synchronism with winding of the roll of film to print data, such as a date, as a dot matrix image.
This type of data printing device is generally located such that the printing on the film occurs between an aperture, through which the film is exposed, and a spool chamber, into which the film is wound. That is, the printing occurs at a position that is downstream of the photographing position along the film winding direction, since the data is printed on the exposed frame after exposure (photographing). Thus, the data printing device, and in particular the imaging optical system, must be arranged between a photographing optical path, leading from a photographing lens through the aperture, and the spool chamber.
There are three types of imaging optical systems used in conventional data printing devices. The first type of imaging optical system uses a straight optical path between the light emitting device and the film. Thus, this imaging optical system has no reflecting surfaces. The second type of imaging optical system includes a single reflecting surface to reflect a light from the light emitting device through a right angle (90 degrees) toward the film. The third type of imaging optical system includes two reflecting surfaces that are parallel to each other such that light from the light emitting device is shifted parallel to the direction of travel in the path to the film.
However, the conventional data printing devices described above require a relatively large clearance between the photographing optical path and the spool chamber.